1. Field of the Invention
The present invention pertains to a rear view mirror for a vehicle comprising a mirror housing, an antenna module arranged on the backside of said mirror housing for receiving data of at least one radio data service, an electronic display unit being arranged on the front side of said mirror and an electronic unit in electrical communication with said antenna module and said display unit for displaying at least portions of said data received by said antenna module onto said display unit, wherein an antenna module sealing mechanism hiding said antenna module inside a casing of said mirror housing in a deactivated state and exposing said antenna module towards a driving direction/windscreen side in an activated state, whereby said antenna module is arranged in a recess of said mirror housing and said antenna module sealing mechanism comprises a slidable or pivotable door opening said recess in the activated state and closing said recess in the deactivated state wherein said antenna module sealing mechanism comprises an electromotor unit for opening and closing said door.
2. Description of the Related Art
Modern vehicles are equipped with at least one rear view mirror for observing backward traffic. Outside rear view mirrors are often mounted onto a door or near to a door pillar onto the vehicle's outer chassis while inside rear view mirrors are usually mounted onto the vehicle's inner roof or onto an inside surface of the front windscreen. In recent times, such rear view mirrors are increasingly equipped with information displays informing a driver about clock-time, compass direction, outer temperature or other sensor data.
On the other hand, various modern board navigation, communication and entertainment systems, such as navigation systems, mobile phones, DAB radios (Digital Audio Broadcasting), DMB receivers (Digital Multimedia Broadcasting) etc., depend on high frequency radio data services which require high-quality radio signal reception in a microwave frequency range. A degraded radio signal reception decreases the receiving rate of microwave signals from navigation satellites or multimedia and communication service antennas, such that the radio data service malfunctions or breaks down, thus annoying the driver and effecting his/her driving behavior. A high-quality signal reception quality can be provided by a direct line of sight and an exact alignment towards a transmitting station, such as a satellite or a base station antenna. As a consequence, placing an antenna in the vicinity of the front windscreen offers an optimal line of sight in a driving direction but a fixed installation of one or multiple antennas inside the passenger cabin, particularly near to the front windscreen, can disturb a driver's view onto the street ahead. On the other hand, a temporary installation of one or multiple antennas onto the windscreen also causes problems with a secure attachment of an antenna structure to the windscreen and also affects the driver's sight onto the street. For using multiple radio data services, individual antennas have to be installed, whereby a temporary installation is inconvenient on the part of the driver. Therefore, multi-service antenna modules have been developed comprising one or more antenna structures, preferably for a microwave frequency range of 300 MHz to 500 GHz.
Antenna modules of this generic type can also be used for receiving and transmitting data to an Electronic Toll Collection System (ETCS) allowing toll collection without vehicle stops at toll gates. ETCS relies on a wireless telecommunication between moving vehicles and Road Side Equipment (RSE) set up on roadways. In general ETCS helps to prevent traffic congestions near toll gates and increases traffic safety and speed. Thereby, a reliable radio communication between the on-board ETCS unit and the RSE is extremely vital for the toll system functioning and the driver's safety when driving through toll gates. In case of an unreliable radio reception, vehicles suddenly have to stop because toll gates do not open properly, which can cause rear-end collisions and long traffic jams. As a consequence, a high-quality antenna reception is vital for the driver's safety with respect to a reliable satellite-based traffic navigation, radio-based ETCS and traffic regulation system which demands a high quality radio reception and an exact alignment of the on-board antenna structure towards a satellite, RSE antenna respectively.
From US 2003 0090820 A1 an inside rear view mirror is known which comprises a built-in antenna inside a housing of the rear view mirror. The antenna is designed for ETCS communication and is mounted at an angle of approximately 20° in the up and down direction and parallel to the left and right direction with respect to the vehicle's driving direction. The antenna is mounted inside the mirror housing such that the antenna does not have a direct line of sight to the RSE and the housing material degrades the radio communication quality between integrated antenna and RSE antenna.
CN 201 058 587 Y and CN 201 138 901 Y discloses an rearview mirror with a mirror housing, an antenna module arranged on the backside of said mirror housing, an electronic display unit being arranged on the front side of said mirror and an electronic unit. The rear view mirror further comprises a manually operated antenna module sealing mechanism which can hide and expose said antenna towards a driving direction.
U.S. Pat. No. 6,172,618 B1 describes an attachable rearview mirror being mountable to an existing room mirror of a vehicle, said rearview mirror consists of a mirror housing, an antenna module arranged on the backside of said mirror housing and an electronic display unit being arranged on the front side of said mirror. The antenna module is adjustably mounted and can be directed towards a driving direction of the vehicle.